Nitrite in exhaled breath condensate as a marker of nitrossative stress in the airways of patients with asthma, COPD, and idiopathic pulmonary fibrosis
Abstract
Nitrite and nitrate were assayed in the exhaled breath condensate (EBC) of 14 atopic patients with mild-to-moderate stable asthma, 18 atopic asthmatics with exacerbation, 14 COPD patients without exacerbation, 18 patients with exacerbated COPD, 13 patients with active IPF, and in 29 healthy subjects. The geometric mean [exp(mean+-SD)] EBC concentrations of nitrite (micromol/l) in patients with asthma [5.1(2.1-12.3)], exacerbation of asthma [5.1(2.8-9.6)], exacerbation of COPD [5.3(3.2-8.7)], and with IPF [5.5(2.9-10.2)] were higher (P<0.05) compared with those of healthy subjects [2.9(1.6-5.3)] and patients with stable COPD [3.0(1.3-6.7)].
Nitrite concentration increased with decreased lung function of patients with asthma (r(s)=-0.31, P<0.02). In conclusion, EBC nitrite is a suitable marker of nitrossative stress in adult patients with lung diseases but cannot differentiate controlled and exacerbated asthma.
Further improvements to the methods of EBC collection and sample handling are warranted.